Field of the Invention
The present invention relates to a pneumatic tire, and in particular to a pneumatic tire that may exhibit better wear resistance.
Description of the Related Art
In order to improve the wear resistance of tires, measures have been carried out such as increasing the content of butadiene rubber (BR) in tread rubber and employing a design to increase the depth of grooves in a tread pattern. However, the tires of increased content of butadiene rubber in the tread rubber, in general, are deteriorated in the wet grip performance. The tires with increased depth of grooves may improve the drainage performance but can deteriorate the rigidity of the tread portion, which adversely affects the steering stability of the tire.
Japanese Unexamined Patent Application Publication No. 10-100615 proposes a pneumatic tire including a tread portion with a pair of shoulder portions. Each of the shoulder portions is divided by a sub groove into an axially inner land portion and an axially outer land portion to restrain partial wear such as heel-and-toe wear of the tire without deterioration of the wet performance. The outer land portion is further divided by a lateral grooves and the inner land portion is formed as a rib that continuously extends in the circumferential direction.